[RESOLVED] Why does the header() function work on my local host but not the remote host??

[Paul_help_]

Hi guys.

The header function is making me pull my hair out!

My question is simple --- Why does the header() function work on my local host but not the remote host??

It works perfect on localhost but not the remote host.

I doubt it has anything to do with the server - as all my other php code works fine.

Paul.

[pbismad]

There's two possibilities -

1) Your code is outputting something to the browser before the header() statement, causing it to fail. Unfortunately, php has a setting that hides this problem, allowing code to work on one server but not another. Use a phpinfo(); statement in a .php script file and check what the output_buffering setting is, on both the local development system and on the live server. If it's ON, on your development system, you should turn it off, so that the code you spend your time developing will work when it gets moved to a server that has this setting turned off, and where you may not have the ability to modify the setting.

2) When you moved the file(s) to the live server, you may have edited some of them, and your editor saved them with BOM (Byte Order Mark) characters, which is output that prevents the header() statement from working. In this case, make sure that your editor saves the file without any BOM characters.

If you set php's error_reporting to E_ALL and display_errors to ON, the result error message will help pin down which of these cases are the cause of the problem. If the output being sent to the browser is occurring on line 1 of your main file and you don't have anything in your code on line 1 that's sending output, the problem is due to the BOM characters that were saved with the file.

[NogDog]

One other possibility would be if your server's PHP config has an auto_prepend_file configured, and that file causes something to be output (which can even be something as trivial as a newline after a closing "?>" tag -- which is the main reason to avoid using closing ?> tags on PHP files that do not actually output anything.

PS: this would show up in the above-recommended error reporting, too, should it be the case.

[Paul_help_]

Thanks guys.

I think the best thing to do is to just send you an example of my code so you can see for yourselves what my problem is.

Basically, I have been building a client a customer review application for there website. Its just an area where customers can leave testimonials.

But there is only two files we need to look at in order to pinpoint where I am going wrong when using the header() function.

Below is the code where I actually use the header function:

file name: common.inc.php:

<?php
require_once "../config.php";
require_once "../dataObjectClass.php";
require_once "../testimonialClass.php";
require_once "adminClass.php";
function checklogin(){
session_start();
if( !$SESSION["user"] ){
!$SESSION["user"] = "";
header( "Location: login.php" );
exit;
}
}
?>

......... the above document has absolutely no spaces at all before or after the opening and closing php tags. And I have just been really careful to eliminate ANY spaces. And I am still having no luck.

The below document is where I include and use the above document's function:

file name: admin.php:

<?php

require_once "common.inc.php";

checklogin();

echo "<br><h1 style='text-align: center;'>Welcome Mike!<br><br>Displaying all of your reviews:</h1><br>";

echo "<h3 style='color: blue; text-align: center;'><span style='color: black;'>NOTE - </span>Click the <span style='color: red;'>'delete'</span> button under a specific review (displayed below) if you don't want it to be displayed on your website:</h3>";

echo "<h3 style='color: blue; text-align: center;'><span style='color: black;'>IMPORTANT - </span>Please be sure to <span style='color: red;'>'logout'</span> (for the safety of your website) once you have finished making edits!</h3><br>";

$testimonials = testimonial::getAllTestimonials();

echo "<hr style='margin-top: 30px;'>";

foreach( $testimonials as $testimonial ){

echo "<div style='text-align: center; margin-bottom: 30px; margin-top: 30px;'>";

echo "<b style='font-size: 25px;'>" . ucfirst($testimonial->getValue( "firstname" )) . " " . ucfirst($testimonial->getValue( "lastname" )) . "</b><br>";
echo ucfirst($testimonial->getValue( "comment" )) . "<br>";
echo "<a href='admin.php?delete=" . $testimonial->getValue( "id" ) . "'>Delete</a>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<a href='logout.php'>Logout</a>";
echo "<hr style='margin-bottom: 30px; margin-top: 30px;'>";

echo "</div>";

}

echo "<br><p style='text-align: center;'><a href='logout.php' style='font-size: 30px;'>Logout</a></p><br><br>";

$deleteById = isset( $GET["delete"] ) ? (int)$GET["delete"] : "";

if( $deleteById ){

testimonial::deleteTestimonial( $deleteById );

}

?>

To explain my problem in more detail - If I am not logged in to the admin area, and i try to view the admin.php page, the above could is intended to redirect me to the login page. But what happens is I don't get redirected to the login.php page and I just stay on the admin.php page and it is just a blank page displaying nothing. I just want it to redirect to login.php.

..... As you can see, the second document does have spaces (etc). But this can't be the reason why the function (containing the header() function) in the first file (above) isn't working, can it?

I don't know where I am going wrong.

Please help me!

Paul.

[NogDog]

Please use [noparse]

...

[/noparse] tags around your code snippets.

I'd start with this:

<?php
// let's see all errors/warnings/notices for now:
ini_set('display_errors', true); // set to false in production when ready
error_reporting(E_ALL);

require_once "../config.php";
require_once "../dataObjectClass.php";
require_once "../testimonialClass.php";
require_once "adminClass.php";
function checklogin(){
    session_start();
    if( empty($_SESSION["user"])){       // safer way to write this
        $_SESSION["user"] = "";          // removed '!' before the '$'
        header( "Location: login.php" ); // really should use full URI here
        exit;
    }
}
// delete closing php tag in case something adds a newline to the end of file

[sneakyimp]

In my experience, this difference in behavior between my workstation (localhost) and the server is almost always because the server has a different error_reporting setting or something and is outputting E_NOTICE or E_WARNING type stuff. For example:

error_reporting(E_ALL); // turn error reporting all the way up. NOTE: this might be the default setting in your php.ini file

echo $some_var; // because I haven't defined this var yet, it causes an E_NOTICE error to be output.

header("location: some-other-file.php"); // this won't work because the script already started output with the E_NOTICE error above, 
// outputs Warning: Cannot modify header information - headers already sent error

You might want to carefully inspect the output of your script to see if you are getting any errors before you attempt to call the header function.

[Paul_help_]

NogDog.

// really should use full URI here

.... You mean the full URL?

and:

// delete closing php tag in case something adds a newline to the end of file

.... How on earth will the php code function without a closing php tag?

Paul.

[dalecosp]

Paul help!;11061919 wrote:

.... You mean the full URL?

Yes, but no ... URI is correct: https://en.wikipedia.org/wiki/Uniform_Resource_Identifier

In practice, the two terms are often used interchangeably.

.... How on earth will the php code function without a closing php tag?

It works Just Fine(TM). You only need a closing PHP tag if there's, for example, plain HTML output in the same file after the PHP code (which is something most of us try to avoid if at all possible, but I'll bet everyone here can lay hands on at least ONE file that has something else at the end of a file ....

<?php

//paul.php

echo "Hi Paul!\n";

$a = $x = 4;

$sum = 56 + ($a * $x);

echo "The sum is: $sum" . PHP_EOL; // note, no ending PHP tag!

I can ask the parser to check "paul.php":

[507] Thu 11.May.2017 9:38:16
[admin@link][~]
$ php -l paul.php
[I]No syntax errors detected in paul.php[/I]

Running paul.php:

[507] Thu 11.May.2017 9:38:16
[admin@link][~]
$ php paul.php
[i]Hi Paul!
The sum is: 72[/i]